Optical polarizer
Meadowlark Optics
Ideal linear polarizers allow the transmission of only one linear polarization state with zero leakage of the orthogonal linear polarization state and rotating the linear polarizer about the optical axis changes the output plane of polarization. Thus, an ideal linear polarizer transmits only 50% of an unpolarized input beam and two ideal polarizers with their transmission axes crossed totally extinguish an incident beam. Imperfections in polarizers such as scattering sites, material defects (such as pinholes in thin films) and field-of-view effects reduce a polarizer's contrast from ideal.
When choosing a linear polarizer, several key factors must be considered including: wavelength range, aperture size, acceptance angle, damage threshold, cost, transmission efficiency and extinction ratio. Extinction ratio (or contrast ratio) is defined as the ratio of transmitted intensity through parallel polarizers to the transmitted intensity through crossed polarizers. Meadowlark Optics offers several types of polarizers with extinction ratios as high as 10,000,000:1 over the operating wavelength range.
